Rising sea a threat to riverside homes

Nicole Hasham

WATER will swamp homes and businesses from Haberfield to Homebush as rising sea levels inundate the Parramatta River foreshore over the next century, a new analysis shows.

The findings are critical as valuable river frontage becomes increasingly urbanised and former industrial sites are redeveloped into housing.

Even under a limited sea level rise of 0.4 metres, predicted by 2050, the area of riverside land submerged every year would increase by 450 per cent on current levels.

Once the sea level rises to 0.9 metres, which is forecast by the end of the century, residential land in the lower estuary, which covers suburbs including Haberfield, Rodd Point and Drummoyne, could be inundated annually.

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More homes at Haberfield and Drummoyne and residential land at Canada Bay and Meadowbank could be engulfed every 100 years, on average.

Water would also threaten industrial land at Homebush Bay, Homebush, Rydalmere and Rosehill, golf courses at Five Dock and Concord, roads at Chiswick, open space at Lilyfield and parks in other suburbs.

The report by consultants Cardno, presented to Parramatta Council late last month, is believed to be the first such coastal hazard assessment of the Parramatta River estuary.

It is based on United Nations sea level forecasts previously used by councils to map hazard areas. Those benchmarks were dumped by the O'Farrell government in September, prompting criticism that the new policy would confuse councils trying to manage climate change effects.

The report shows 1180 lots are at risk of inundation once a year. This would jump to 2270 lots under a 0.9-metre sea level rise.

As well as damaging land and buildings, inundation could affect the estuarine ecology, disrupt the stormwater network and cause economic loss and "human injury or stress", the report said.

It could also render parks and open space unviable for public use and restrict emergency vehicle access.

The findings are part of a broader draft plan to guide future management of the estuary, which recommended restriction of new foreshore developments in areas at risk of inundation, stormwater network upgrades and a more co-ordinated strategic planning approach.

Eight councils and at least eight government agencies have responsibility for the river, complicating efforts to manage climate change impacts.

The report showed significant inundation could occur at Wentworth Point, near Homebush Bay, part of which is zoned for homes.

A spokesman for the Planning Department said it considered sea level rise when assessing approved residential development, including building setback and the location of basements and ground floors.

The analysis also revealed inundation would be likely on residential land at Rhodes. A spokeswoman for Canada Bay Council said the images depicted the land before remediation was complete, and it was now "well above the sea level".

The Sydney Coastal Councils Group chief executive, Geoff Withycombe, said funding for councils to assess hazards posed by sea level rise was inadequate.

"As land becomes more and more scarce we are increasingly pushing development into hazardous areas, and that's a real concern," he said.

More sophisticated flooding and inundation maps would give councils "more evidence and justification to restrict development" and ensure appropriate dwellings were built on vulnerable land, he said.

A former chairman of the Coastal Council of NSW and member of the Wentworth Group of Concerned Scientists, Bruce Thom, said theParramatta River was less vulnerable to sea level rise than other NSW waterways with larger catchments and more low-lying land.